I wonder how much of that is coming from the interconnection with the Disney+ TV series now. Those 6 hours allow a lot more breathing room and character development and then the cinema entries are kind of the more shallow all action cgi fests you describe. Wanda certainly has a major arc she's gone through, and I think they did a good job giving Strange an arc by showcasing a very classic “tragic flaw” and his struggle against it. (Being vague of course for spoiler avoidance! 😆)